Atlanta , Georgia -LRB- CNN -RRB- -- A third beluga whale belonging to the world 's largest aquarium has died , the Georgia Aquarium announced late Monday .

The exact cause of Nico 's sudden death on Saturday is inconclusive from the initial necropsy or animal autopsy . The Georgia Aquarium hopes to find out more information in the months ahead from a more detailed necropsy .

`` As we work with and care for the many animals at the Georgia Aquarium , we become attached emotionally , '' said Dr. Gregory D. Bossart , chief veterinary officer at the aquarium . `` The loss is not unlike that of faithful dog or special horse that has been a part your life for years . ''

Nico died at Sea World in San Antonio , where he and two other beluga whales had been moved temporarily while the Georgia Aquarium is undergoing renovation . Nico was scheduled to return home to Atlanta next month with companions Maris and Natasha .

Nico arrived in Atlanta with Gaspar , two whales obtained from a park in Mexico . Both animals suffered `` significant health issues '' from their times in a foreign park and were essentially `` living on borrowed time , '' said Bossart , who had been caring for the two whales as far as nine years ago , while they were still in Mexico .

`` We rescued Nico knowing that he had health issues due to his prior home , but we were confident that we could provide a better quality of life for his final years , '' Bossart said .

Gaspar was suffering from a bone disease contracted before arriving at the downtown Atlanta aquarium and was euthanized in January 2007 . Another beluga whale , Marina , died 11 months later from complications of old age .

Beluga whales or white whales , whose name is derived from a Russian word meaning white , typically live in Arctic and sub-Arctic regions including Canada , Russia , Greenland and the U.S. state of Alaska . They can live up to 35 years .

The belugas are not the only high-profile deaths at the Georgia Aquarium , which opened in late 2005 . A pair of whale sharks have also died at the eight-million-gallon facility , the only one outside Asia to display the giant fish .

CNN 's Dave Alsup contributed to this report .

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After autopsy , the cause of Nico 's sudden death Saturday is inconclusive

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Nico died at Sea World in San Antonio , where he was kept temporarily

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The Georgia Aquarium is undergoing renovations , which is why Nico was moved